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From:   Chuck Lever <chuck.lever@oracle.com>
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Subject: fix_priv_head
Message-Id: <3799C9E0-DFF3-450C-A815-14BAFAC97EA8@oracle.com>
Date:   Thu, 23 Jul 2020 13:46:19 -0400
Cc:     Linux NFS Mailing List <linux-nfs@vger.kernel.org>
To:     Bruce Fields <bfields@fieldses.org>
Sender: linux-nfs-owner@vger.kernel.org
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Hi Bruce-

I'm trying to figure out if fix_priv_head is still necessary. This
was introduced by 7c9fdcfb1b64 ("[PATCH] knfsd: svcrpc: gss:
server-side implementation of rpcsec_gss privacy").

static void
fix_priv_head(struct xdr_buf *buf, int pad)
{
        if (buf->page_len == 0) {
                /* We need to adjust head and buf->len in tandem in this
                 * case to make svc_defer() work--it finds the original
                 * buffer start using buf->len - buf->head[0].iov_len. */
                buf->head[0].iov_len -= pad;
        }
}

It doesn't seem like unwrapping can ever result in a buffer length that
is not quad-aligned. Is that simply a characteristic of modern enctypes?

--
Chuck Lever